Pedestrian protection apparatus for vehicle

ABSTRACT

A pedestrian protection apparatus for a vehicle, including: a plate member, which includes front and rear portions, and which is fixed at the rear portion to the vehicle; and at least one reinforcing bead each formed integrally on the front portion of the plate member and each including a bead-extending portion and a bead-end portion which extends integrally from a rear-side edge of the bead-extending portion for connecting the rear-side edge and the rear portion of the plate member, the apparatus being arranged to sweep a leg portion of a pedestrian that has collided with the front of the vehicle by contact of a front end of the plate member with the leg portion, thereby protecting the leg portion, wherein a connecting portion between the bead-end portion and the rear portion of the plate member is gently curved without being folded.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.11/617,816, filed Dec. 29, 2006, which claims the benefit of JapanesePatent Application Nos. 2006-164270 and 2006-164271 both filed on Jun.14, 2006, the contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates in general to a pedestrian protectionapparatus for a vehicle, and in particular to an improved structure ofthe pedestrian protection apparatus disposed at a lower part of a frontface of the vehicle and arranged to sweep a lower part of a leg portionof a pedestrian by contact with the lower part of the leg portion of thepedestrian that has collided with or contacted the front face of thevehicle, thereby protecting the leg portion of the pedestrian.

2. Discussion of Related Art

In vehicles such as automotive vehicles, there are conventionallydisposed, at a front face, a rear face, or side faces, of the vehicles,various types of protection apparatus which absorb an impact energygenerated upon a collision for thereby protecting a vehicle body andvehicle passengers. In recent years, there is disposed, at the frontface of the vehicle, an apparatus for protecting a pedestrian uponcollision or contact of the pedestrian with the front face of thevehicle.

As one type of the pedestrian protection apparatus, there is known aso-called leg-sweep apparatus which is disposed inside of a front bumperor disposed at a lower part of the front bumper independently of thefront bumper. The leg-sweep apparatus is arranged to apply, to a lowerpart of a leg portion of the pedestrian, a counterforce with respect toan impact load that is inputted upon collision of the pedestrian withthe front face of the vehicle and sweep (scoop up) the lower part of theleg portion of the pedestrian, thereby causing the pedestrian to falldown or to be thrown over toward the vehicle. Thus, it is possible tominimize occurrence of injuries to the leg portion of the pedestriansuch as bone fractures, thereby assuring protection and safety of thepedestrian.

Examples of the leg-sweep apparatus as one type of the pedestrianprotection apparatus are disclosed in a patent publication document 1(JP-A-2001-277963), a patent publication document 2 (JP-A-2004-25976),and a patent publication document 3 (JP-A-2004-203183), for instance.The pedestrian protection apparatus disclosed in the patent publicationdocument 1 is arranged to be disposed at the lower part of the front ofthe vehicle and includes: a resin foam body which extends in a vehiclewidth direction and at least a part of which protrudes from the frontface of the vehicle; and a beam member which extends in the vehiclewidth direction while being in contact with the back surface of theresin foam body. The pedestrian protection apparatus disclosed in thepatent publication document 2 is formed of a metal pipe or the like andis fixed to the lower part of the front face of the vehicle so as toextend in the vehicle width direction. The pedestrian protectionapparatus disclosed in the patent publication document 3 includes: aplate member located so as to extend in a frontward and backward of thevehicle and fixed to the lower part of the front of the vehicle; and aplurality of flat ribs disposed on a front portion of the plate memberso as to extend upright therefrom, so that the front portion of theplate member has an increased rigidity. Further, a rear portion of theplate member has a flat plate-like configuration extending in thefrontward and backward direction of the vehicle. The thus constructedapparatus is fixed to the vehicle at a rear-side end section of the rearportion of the plate member. However, the pedestrian protectionapparatus disclosed in those documents have drawbacks which should berectified.

The pedestrian protection apparatus disclosed in the patent publicationdocument 1 needs a large number of components, inevitably pushing up thecost of the components. Further, it is cumbersome to install theapparatus on the vehicle. The pedestrian protection apparatus disclosedin the patent publication document 2 inevitably has a large weight.Further, it is difficult to form the apparatus to have a configurationcorresponding to that of the front face of the vehicle.

The pedestrian protection apparatus disclosed in the patent publicationdocument 3 ensures a sufficiently reduced weight where the plate memberand the plurality of ribs are formed integrally with each other using asynthetic resin material, for instance. Moreover, the apparatusadvantageously achieves excellent formability and a reduction in thenumber of components by employing, in formation of the plate member andthe plurality of ribs, a molding technique using metal dies such asinjection molding. Thus, the drawbacks experienced in the pedestrianprotection apparatus disclosed in the patent publication documents 1 and2 are eliminated in the apparatus disclosed in the patent publicationdocument 3. The apparatus disclosed in the patent publication document3, however, suffers from some obstacles to improvement in impactperformance described below.

Namely, the pedestrian protection apparatus disclosed in the patentpublication document 3 enables, upon contact with the leg portion of thepedestrian, the impact load in the load characteristics to rise promptlyand reach a target value quickly, thus ensuring excellent impactperformance that permits a sufficient high degree of counterforce withrespect to the impact load to be instantaneously exhibited. To this end,the height of each of the ribs provided on the front portion of theplate member needs to be increased to give sufficient rigidity to thefront portion of the plate member to which the impact load is inputtedfor thereby preventing the front portion from being easily deformed. Theincrease in the height of each rib, however, increases the weight of thepedestrian protection apparatus as a whole even when the apparatus isconstituted by a resin-molded product. In this instance, the merit ofthe resin-molded product, i.e., lightness, is considerably deteriorated.Further, where the height of each rib is increased, it is required thatmetal molds to be used in molding be formed with a recessed portionhaving a large depth for forming each rib. In this instance, it takesadditional time to manufacture the metal mold. Moreover, the moldrelease characteristics may be deteriorated. In consequence, there maybe caused a problem of deterioration in manufacturing efficiency of thepedestrian protection apparatus as a whole.

Under the situations mentioned above, a patent publication document 4(JP-A-2002-264741) discloses a pedestrian protection apparatus in whichreinforcing beads are formed integrally on the front portion of theplate member in place of the flat plate-like ribs. Each reinforcing ribincludes: an extending portion which extends in a frontward and backwarddirection of the vehicle with a channel-like configuration that is opendownward; and a plate-like end portion which extends integrally from arear-side edge of the extending portion for connecting the rear-sideedge of the extending portion and the rear portion of the plate member.The thus constructed pedestrian protection apparatus ensures the samedegree of rigidity at the front portion of the plate member as thatensured when the flat plate-like ribs with a large height are formedintegrally on the front portion of the plate member, while keeping thedepth or the height of each reinforcing bead relatively small.Accordingly, the pedestrian protection apparatus disclosed in the patentpublication document 4 eliminates not only the above-mentioned drawbacksexperienced in the pedestrian protection apparatus disclosed in thepatent publication documents 1, 2, but also the above-mentioned problemexperienced in the pedestrian protection apparatus disclosed in thepatent publication document 3.

The inventors of the present invention conducted various experiments andstudied the pedestrian protection apparatus disclosed in the patentpublication document 4. As a result of the study, it was found that theapparatus had the following drawbacks.

Namely, in the pedestrian protection apparatus disclosed in the patentpublication document 4, a connecting portion between the end portion ofeach reinforcing bead and the rear portion of the plate member is formedas an angular folded or bent portion, so that stress is applied to suchfolded portion upon inputting of the impact, resulting in comparativelyeasy flexing deformation of the plate member at a boundary between itsfront and rear portions at which such folded portion is located. Inconsequence, there may be caused a delay in rise of the impact load inthe load characteristics, rendering it difficult for the impact load toinstantaneously reach the target value. Thus, the pedestrian protectionapparatus disclosed in the patent publication document 4 does not ensuresatisfactory impact performance that permits a sufficiently high degreeof counterforce with respect to the impact load to be instantaneouslyexhibited.

In the pedestrian protection apparatus disclosed in the patentpublication document 4, because the connecting portion between the endportion of each reinforcing bead and the rear portion of the platemember is formed as the angular folded portion as described above, theinner (anterior) surface of the end portion assumes a flat planeconfiguration. Accordingly, during running of a vehicle on which theapparatus is mounted, a portion of the air flow flowing through thelower part of the vehicle in the backward direction, which portion ofthe air has entered the inside of the reinforcing bead, is brought intohard contact with the inner (anterior) surface of the end portion havingthe flat plane configuration, thereby causing a large air resistancethat may lead to a deterioration in the aerodynamic characteristics ofthe pedestrian protection apparatus and accordingly of the vehicle.

The inventors of the present invention conceived of providing flatplate-like auxiliary ribs each extending continuously in the frontwardand backward direction over the end portion of each reinforcing bead andthe front-side end section of the rear portion of the plate member, inan attempt to increase the strength of the plate member with respect todeformation (deformation strength) at its boundary portion between thefront and rear portions where the connecting portion (folded potion)between the end portion of each reinforcing bead and the rear portion ofthe plate member is located.

The inventors have conducted a known collision test using the pedestrianprotection apparatus having such auxiliary ribs. The result of thecollision test indicated the following: Although the boundary portionbetween the front and rear portions of the plate member is preventedfrom being deformed, stress concentrates, upon inputting of the impactload, on two locations at which a front end and a rear end of eachauxiliary rib are located because the connecting portion of eachauxiliary rib with the plate member has a linear configuration. In thisinstance, the plate member tends to be easily subjected to flexingdeformation at portions thereof corresponding to the above-indicated twolocations at which the front and rear ends of each auxiliary rib arerespectively located, thus rendering it difficult for the pedestrianprotection apparatus to ensure the desired impact performance asdescribed above.

SUMMARY OF THE INVENTION

The present invention was made in the light of the above-describedsituations. It is therefore an object of the invention to provide apedestrian protection apparatus for a vehicle which is capable ofeffectively ensuring excellent impact performance that permits asufficient high degree of counterforce with respect to the impact loadto be instantaneously exhibited.

The above-indicated object of the present invention may be attainedaccording to a first aspect of the invention, which provides apedestrian protection apparatus for a vehicle, comprising: a platemember which is disposed at a lower part of a front of the vehicle so asto extend in a frontward and backward direction of the vehicle, whichincludes a front portion and a rear portion, and which is fixed at therear portion to the vehicle; and at least one reinforcing bead eachformed integrally on the front portion of the plate member and eachincluding a bead-extending portion which extends in the frontward andbackward direction of the vehicle with a channel-like configuration thatis open upward or downward and a bead-end portion which has a plate-likeconfiguration and which extends integrally from a rear-side edge of thebead-extending portion for connecting the rear-side edge of thebead-extending portion and the rear portion of the plate member, theapparatus being arranged to sweep a leg portion of a pedestrian that hascollided with the front of the vehicle by contact of a front end of theplate member with the leg portion of the pedestrian, thereby protectingthe leg portion of the pedestrian, wherein a connecting portion betweenthe bead-end portion of each of the at least one reinforcing bead andthe rear portion of the plate member is gently curved without beingfolded.

Unlike the conventional apparatus wherein the connecting portion betweenthe end portion of each reinforcing bead and the rear portion of theplate member is formed as the angular folded portion, the pedestrianprotection apparatus constructed as described above does not suffer fromstress concentration on one location in the connecting portion uponinputting of the impact. Instead, the stress is distributed over anentirety of the gently curved connecting portion between the bead-endportion of each of the at least one reinforcing bead and the rearportion of the plate member. Thus, the plate member is prevented frombeing easily subjected to flexing deformation at the boundary portionbetween its front and rear portions at which the connecting portionbetween the bead-end portion of each of the at least one reinforcingbead and the rear portion of the plate member is located. As a result,it is possible to effectively avoid occurrence of a delay in the rise ofthe impact load in the load characteristics arising from such easyflexing deformation of the plate member.

In the above-described pedestrian protection apparatus wherein theconnecting portion between the bead-end portion of each of the at leastone reinforcing bead and the rear portion of the plate member is formedto have the gently curved configuration without being folded, a sectionof the inner surface of the bead-end portion, which is nearer to theconnecting portion and which is remote from the bead-extending portion,is constituted to have the gently curved configuration. According to thearrangement, when the air flow which flows through the lower part of thevehicle and enters the inside of the reinforcing bead during running ofthe vehicle on which the present apparatus is mounted is brought intocontact with the inner surface of the bead-end portion, the air flowcontacted the gently curved section of the inner surface of the bead-endportion can smoothly flow in the backward direction of the vehicle whilebeing guided by the gently curved surface. Accordingly, it is possibleto effectively prevent the air flow entered the inside of thereinforcing bead from being brought into hard contact with respect tothe entirety of the inner surface of the bead-end portion.

The pedestrian protection apparatus constructed according to theabove-indicated first aspect of the invention allows the impact load inthe load characteristics to rise promptly and reach the target valuequickly, thereby effectively ensuring excellent impact performance thatenables a sufficient counterforce to be instantaneously exhibited withrespect to the impact load. In addition, the air resistance can beadvantageously reduced, effectively achieving an improvement in theaerodynamic characteristics. In consequence, the leg portion of thepedestrian collided with the front face of the vehicle can be promptlyand reliably swept, thereby assuring sufficient protection of the legportion of the pedestrian. Moreover, the present apparatusadvantageously assures an improvement in running stability and fueleconomy of the vehicle based on excellent aerodynamic characteristics.

The above-indicated object of the present invention may be attainedaccording to a second aspect of the invention, which provides apedestrian protection apparatus for a vehicle, comprising: a platemember which is disposed at a lower part of a front of the vehicle so asto extend in a frontward and backward direction of the vehicle, whichincludes a front portion and a rear portion, and which is fixed at therear portion to the vehicle; and at least one reinforcing bead eachformed integrally on the front portion of the plate member and eachincluding a bead-extending portion which extends in the frontward andbackward direction of the vehicle with a channel-like configuration thatis open upward or downward and a bead-end portion which has a plate-likeconfiguration and which extends integrally from a rear-side edge of thebead-extending portion for connecting the rear-side edge of thebead-extending portion and the rear portion of the plate member, theapparatus being arranged to sweep a leg portion of a pedestrian that hascollided with the front of the vehicle by contact of a front end of theplate member with the leg portion of the pedestrian, thereby protectingthe leg portion of the pedestrian, the apparatus further comprising atleast one first auxiliary bead each having a width smaller than a widthof each of the at least one reinforcing bead and each extendingcontinuously in the frontward and backward direction of the vehicle overthe bead-end portion of a corresponding one of the at least onereinforcing bead and a front-side end section of the rear portion of theplate member.

In the pedestrian protection apparatus constructed according to theabove-described second aspect of the invention, a connecting portionbetween the bead-end portion of each of the at least one reinforcingbead and the rear portion of the plate member is formed as a bentportion located at a boundary portion between the front and rearportions of the plate member, but there is provided a first auxiliarybead at the bent portion. Accordingly, the present arrangement iseffective to prevent occurrence of stress concentration at the bentportion upon inputting of the impact, thereby avoiding deformation ofthe plate member at the boundary portion between the front and rearportions at which the bent portion is located.

In the present apparatus as described above, a connecting portion ofeach of the at least one first auxiliary bead with respect to thecorresponding reinforcing bead and the rear portion of the plate memberassumes a rectangular configuration, unlike the above-indicatedarrangement in which the flat reinforcing ribs are provided forincreasing the deformation strength of the boundary portion between thefront and rear portions of the plate member. Therefore, stress to begenerated when the impact is inputted to the plate member is distributedover four locations corresponding to four corner portions of therectangle constituted by the connecting portion of the first auxiliarybead with respect to the corresponding reinforcing bead and the platemember, thus advantageously reducing or mitigating the stress generatedat the four locations. Moreover, each of the at least one firstauxiliary bead has a width smaller than the width of each of the atleast one reinforcing bead. Therefore, even when the connecting portionof the first auxiliary bead and the rear portion of the plate member ismade as the bent portion, it is possible to effectively avoid occurrenceof a large magnitude of stress concentration over the entirety of thebent portion upon inputting of the impact. Thus, the plate member iseffectively prevented from being easily subjected to flexing deformationat the connecting portion of each first auxiliary rib with respect tothe corresponding reinforcing rib and the rear portion of the platemember. As a result, not only the above-indicated boundary portion ofthe plate member, but also the entirety of the plate member can beprevented from being easily flexed upon inputting of the impact.

The pedestrian protection apparatus constructed according to theabove-indicated second aspect of the invention allows the impact load inthe load characteristics to rise promptly and reach the target valuequickly, thereby effectively ensuring excellent impact performance thatenables a sufficient counterforce to be instantaneously exhibited withrespect to the impact load. In consequence, the leg portion of thepedestrian collided with the front face of the vehicle can be promptlyand reliably swept, thereby assuring sufficient protection of the legportion of the pedestrian.

FORMS OF THE INVENTION

The present invention is preferably practiced in at least the followingforms.

(1) A pedestrian protection apparatus for a vehicle, comprising: a platemember which is disposed at a lower part of a front of the vehicle so asto extend in a frontward and backward direction of the vehicle, whichincludes a front portion and a rear portion, and which is fixed at therear portion to the vehicle; and at least one reinforcing bead eachformed integrally on the front portion of the plate member and eachincluding a bead-extending portion which extends in the frontward andbackward direction of the vehicle with a channel-like configuration thatis open upward or downward and a bead-end portion which has a plate-likeconfiguration and which extends integrally from a rear-side edge of thebead-extending portion for connecting the rear-side edge of thebead-extending portion and the rear portion of the plate member, theapparatus being arranged to sweep a leg portion of a pedestrian that hascollided with the front of the vehicle by contact of a front end of theplate member with the leg portion of the pedestrian, thereby protectingthe leg portion of the pedestrian, wherein a connecting portion betweenthe bead-end portion of each of the at least one reinforcing bead andthe rear portion of the plate member is gently curved without beingfolded.

(2) The apparatus according to the above form (1), wherein the bead-endportion of each of the at least one reinforcing bead is an inclined flatplate or an inclined curved plate extending from the rear-side edge ofthe bead-extending portion toward the rear portion of the plate member.According to this form, the air flow entered the inside of each of theat least one reinforcing bead and contacted the inner surface of itsbead-end portion can smoothly flow in the backward direction of thevehicle while being guided by the entirety of the inner surface of thebead-end portion, whereby the air resistance can be advantageouslyreduced, improving the aerodynamic characteristics.

(3) The apparatus according to the above form (1) or (2), wherein aboundary portion between the bead-extending portion and the bead-endportion of each of the at least one reinforcing bead is gently curvedwithout being folded. Unlike the arrangement wherein the boundaryportion between the extending portion and the end portion of eachreinforcing bead is formed as the angular folded portion, thearrangement according to this form does not suffer from stressconcentration on one location in the boundary portion upon inputting ofthe impact. Instead, the stress is distributed over an entirety of thegently curved boundary portion between the bead-extending portion andthe bead-end portion of each of the at least one reinforcing bead. Thus,the plate member is prevented from being easily subjected to flexingdeformation, assuring, with high reliability, excellent impactperformance that permits a sufficient counterforce to be instantaneouslyexhibited with respect to the impact load.

(4) The apparatus according to any one of the above forms (1)-(3),wherein each of the at least one reinforcing bead further includes, at aforward end thereof, a forward wall portion which is formed integrallywith the bead-extending portion of a corresponding one of the at leastone reinforcing bead, which has a front surface extending in a verticaldirection, and which constitutes at least a part of the front end of theplate member. According to this form, the impact load generated bycollision of the leg portion of the pedestrian is inputted generallyperpendicularly to the forward wall portion which constitutes at least apart of the front end of the plate member, for instance. In thearrangement, it is possible to avoid generation of a force which acts onthe front portion of the plate member so as to lift the front portionupward or lower the front portion downward. Thus, the arrangement allowsthe impact load in the load characteristics to be raised promptly andreach the target value quickly, thereby effectively ensuring excellentimpact performance that enables a sufficient counterforce to beinstantaneously exhibited with respect to the impact load.

(5) A pedestrian protection apparatus for a vehicle, comprising: a platemember which is disposed at a lower part of a front of the vehicle so asto extend in a frontward and backward direction of the vehicle, whichincludes a front portion and a rear portion, and which is fixed at therear portion to the vehicle; and at least one reinforcing bead eachformed integrally on the front portion of the plate member and eachincluding a bead-extending portion which extends in the frontward andbackward direction of the vehicle with a channel-like configuration thatis open upward or downward and a bead-end portion which has a plate-likeconfiguration and which extends integrally from a rear-side edge of thebead-extending portion for connecting the rear-side edge of thebead-extending portion and the rear portion of the plate member, theapparatus being arranged to sweep a leg portion of a pedestrian that hascollided with the front of the vehicle by contact of a front end of theplate member with the leg portion of the pedestrian, thereby protectingthe leg portion of the pedestrian, the apparatus further comprising atleast one first auxiliary bead each having a width smaller than a widthof each of the at least one reinforcing bead and each extendingcontinuously in the frontward and backward direction of the vehicle overthe bead-end portion of a corresponding one of the at least onereinforcing bead and a front-side end section of the rear portion of theplate member.

(6) The pedestrian protection apparatus according to the above form (5),further comprising at least one second auxiliary bead each of which hasa width smaller than a width of each of the at least one reinforcingbead and each of which is formed integrally with the bead-extendingportion of a corresponding one of the at least one reinforcing bead soas to extend in the frontward and backward direction of the vehicle.According to this form, each of the at least one reinforcing bead isreinforced by the corresponding second auxiliary bead, therebyeffectively increasing the rigidity of the front portion of the platemember on which the reinforcing bead is provided. As a result, it ispossible to effectively obtain excellent impact performance that permitsa sufficient counterforce to be instantaneously exhibited with respectto the impact load.

(7) The apparatus according to the above form (6), wherein each of theat least one second auxiliary bead has a channel-like configuration thatis open in a direction opposite to a direction in which each of the atleast one reinforcing bead is open. According to this form, where eachof the at least one reinforcing bead has a channel-like configurationthat is open upward, each of the at least one second auxiliary bead isconstructed to have a channel-like configuration that is open downward.On the other hand, where each of the at least one reinforcing bead has achannel-like configuration that is open downward, each of the at leastone second auxiliary bead is constructed to have a channel-likeconfiguration that is open upward. Therefore, the provision of thesecond auxiliary bead on the bead-extending portion of the reinforcingbead does not increase the height or the depth of the reinforcing bead,avoiding an increase in the size of the plate member as a whole. Thus,the arrangement according to this form effectively attains animprovement in the impact performance without an increase in the size ofthe apparatus as a whole and an increase in the size of the metal moldto be used for forming the apparatus.

(8) The apparatus according to the above form (6) or (7), wherein eachof the at least one first auxiliary bead is continuous with acorresponding one of the at least one second auxiliary bead.

(9) The apparatus according to any one of the above forms (5)-(8),wherein the at least one reinforcing bead comprises a plurality ofreinforcing beads provided on the front portion of the plate member soas to be spaced apart from each other in a width direction of thevehicle, and wherein the apparatus further comprises at least one thirdauxiliary bead each of which has a width smaller than a width of each ofthe plurality of reinforcing beads and each of which is formed betweenany adjacent two of the plurality of reinforcing blades so as to extendcontinuously in the frontward and backward direction of the vehicle overa rear-side end section of the front portion of the plate member and thefront-side end section of the rear portion of the plate member.According to this form, at the boundary portion between the front andrear portions of the plate member, there is provided at least one thirdauxiliary bead between any two of the plurality of reinforcing beadswhich are adjacent to each other in the width direction of the vehicle,thereby assuring increased strength of the boundary portion of the platemember with respect to flexing deformation. In consequence, it ispossible to effectively obtain excellent impact performance that permitsa sufficient counterforce to be instantaneously exhibited with respectto the impact load.

(10) The apparatus according to any one of the above forms (5)-(8),wherein the at least one reinforcing bead comprises a plurality ofreinforcing beads provided on the front portion of the plate member soas to be spaced apart from each other in a width direction of thevehicle, and wherein the apparatus further comprises at least one fourthauxiliary bead each of which has a width smaller than a width of each ofthe plurality of reinforcing beads and each of which is formed betweenany adjacent two of the plurality of reinforcing beads so as to extendcontinuously in the frontward and backward direction of the vehicle at afront-side end section of the front portion of the plate member. Thearrangement effectively increases the rigidity of the front portion ofthe plate member, advantageously attaining the desired impactperformance described above.

(11) The apparatus according to any one of the above forms (5)-(8),wherein the at least one reinforcing bead comprises a plurality ofreinforcing beads provided on the front portion of the plate member soas to be spaced apart from each other in a width direction of thevehicle, and wherein the apparatus further comprises: at least one thirdauxiliary bead each of which has a width smaller than a width of each ofthe plurality of reinforcing beads and each of which is formed betweenany adjacent two of the plurality of reinforcing beads so as to extendcontinuously in the frontward and backward direction of the vehicle overa rear-side end section of the front portion of the plate member and afront-side end section of the rear portion of the plate member; and atleast one fourth auxiliary bead each of which has a width smaller thanthe width of each of the plurality of reinforcing beads and each ofwhich is formed between any adjacent two of the plurality of reinforcingbeads so as to extend in the frontward and backward direction of thevehicle at the font-side end section of the front portion of the platemember, each of the at least one third auxiliary bead being continuouswith a corresponding one of the at least one fourth auxiliary bead.

(12) The apparatus according to any one of the above forms (5)-(11),wherein each of the at least one reinforcing bead further includes, at aforward end thereof, a forward wall portion which is formed integrallywith the bead-extending portion of a corresponding one of the at leastone reinforcing bead, which has a front surface extending in a verticaldirection, and which constitutes at least a part of the front end of theplate member. According to this form, the impact load generated bycollision of the leg portion of the pedestrian is inputted generallyperpendicularly to the forward wall portion which constitutes at least apart of the front end of the plate member, for instance. In thearrangement, it is possible to avoid generation of a force which acts onthe front portion of the plate member so as to lift the front portionupward or lower the front portion downward. Thus, the arrangement allowsthe impact load in the load characteristics to be raised promptly andreach the target value quickly, thereby effectively ensuring excellentimpact performance that enables a sufficient counterforce to beinstantaneously exhibited with respect to the impact load.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features, advantages and technical andindustrial significance of the present invention will be betterunderstood by reading the following detailed description of presentlypreferred embodiments of the invention, when considered in connectionwith the accompanying drawings, in which:

FIG. 1 is a top plan view showing a pedestrian protection apparatusconstructed according to a first embodiment of the invention;

FIG. 2 is a cross sectional view taken along line 2-2 of FIG. 1;

FIG. 3 is an enlarged cross sectional view taken along line 3-3 of FIG.2;

FIG. 4 is an explanatory view showing a state in which the pedestrianprotection apparatus of FIG. 1 is installed on a vehicle;

FIG. 5 is an explanatory view showing a deformation state of thepedestrian protection apparatus of FIG. 1 upon collision of a pedestrianwith a front face of the vehicle;

FIG. 6 is a graph showing relationships between resistance value andvelocity of air flow obtained by CFD for the pedestrian protectionapparatus of the invention and a conventional pedestrian protectionapparatus;

FIG. 7 is a graph showing changes in impact load with time obtained byconducting pedestrian collision tests for the pedestrian protectionapparatus of the invention and the conventional pedestrian protectionapparatus;

FIG. 8 is a top plan view showing a pedestrian protection apparatusconstructed according to a second embodiment of the invention:

FIG. 9 is a cross sectional view taken along line 9-9 of FIG. 8;

FIG. 10 is an enlarged cross sectional view taken along line 10-10 ofFIG. 9;

FIG. 11 is an enlarged cross sectional view taken along line 11-11 ofFIG. 9;

FIG. 12 is an enlarged cross sectional view taken along line 12-12 ofFIG. 9;

FIG. 13 is an explanatory view showing a state in which the pedestrianprotection apparatus of FIG. 8 is installed on a vehicle;

FIG. 14 is an explanatory view showing a deformation state of thepedestrian protection apparatus of FIG. 8 upon collision of a pedestrianwith a front face of the vehicle;

FIG. 15 is a view corresponding to FIG. 1 and showing a modified exampleof the pedestrian protection apparatus of FIG. 8;

FIG. 16 is a cross sectional view taken along line 16-16 of FIG. 15; and

FIG. 17 is a graph showing changes in impact load with time obtained byconducting pedestrian collision tests for the pedestrian protectionapparatus of the invention and a conventional pedestrian protectionapparatus.

DETAILED DESCRIPTION OF THE INVENTION

To further clarify the present invention, there will be described indetail embodiments of the invention with reference to the accompanyingdrawings.

1. First Embodiment

Referring first to FIGS. 1 and 2, there will be explained a leg-sweepapparatus as a pedestrian protection apparatus constructed according toa first embodiment of the present invention. The leg-sweep apparatusgenerally indicated at 10 in FIGS. 1 and 2 is arranged to be installedinside of a front bumper which is disposed at a front face of anautomotive vehicle. As apparent from FIGS. 1 and 2, the presentleg-sweep apparatus 10 includes a base plate 12 as a plate member

The base plate 12 is formed of a synthetic resin material such aspolypropylene or ABS resin and is constituted by a thin planar platehaving a generally rectangular shape. In the base plate 12, thedimension as measured in a direction extending in a leftward andrightward direction in FIG. 1, i.e., the dimension as measured in avehicle width direction or a leftward and rightward (lateral) directionof the vehicle under installation of the leg-sweep apparatus 10 on thevehicle, is made smaller than the vehicle width by a suitable amount,and the dimension as measured in a direction extending in an upward anddownward direction in FIG. 1, i.e., the dimension as measured in afrontward and backward direction of the vehicle (a vehicle length orrunning direction), is made sufficiently smaller than theabove-indicated dimension as measured in the leftward and rightwarddirection. Hereinafter, the above-indicated direction extending in theleftward and rightward direction of the vehicle is referred to as “theleftward and rightward direction” while the above-indicated directionextending in the frontward and backward direction of the vehicle isreferred to as “the frontward and backward direction”.

In the base plate 12, a rear portion which occupies a substantially rearhalf region thereof is made as a flat portion 14 which has a flatplate-like configuration and which includes an upper surface and a lowersurface that extend horizontally under installation of the leg-sweepapparatus 10 on a vehicle. At a rear-side end of the flat portion 14, aplurality of insertion holes 16 (here, five insertion holes 16) intoeach of which a suitable fixing bolt is insertable are formed throughthe thickness of the flat portion 14 such that the insertion holes 16are spaced apart from each other by a suitable distance in the leftwardand rightward direction.

A front portion of the base plate 12 except for the flat portion 14 ismade as a reinforcing portion 18 having a reinforcement structure.Namely, there are formed a plurality of reinforcing beads 20 (here,seven reinforcing beads 20) integrally on an intermediate region of thereinforcing portion 18 except both side-end regions thereof in theleftward and rightward direction. The reinforcing beads 20 are adjacentto and spaced apart from each other by a constant distance in theleftward and rightward direction and provide a sufficient reinforcementstructure.

In detail, each reinforcing bead 20 is constituted by including abead-extending portion 22 which extends continuously in the frontwardand backward direction and a bead-end portion 23 which extends from arear-side edge of the bead-extending portion 22, as shown in FIGS. 1-3.

The bead-extending portion 22 of each reinforcing bead 20 includes: anupper bottom wall portion 24; a vertically extending forward wallportion 26; and two side wall portions 28, 28. The upper bottom wallportion 24 generally has a rectangular shape having a comparativelysmall width and is located at a height position which is higher by asuitable distance than an upper surface of each of flat plane-like sideportions 30 (which will be described) and the upper surface of the flatportion 14 which is flush with and continuous with the upper surface ofeach side portion 30, such that the upper bottom wall portion 24 extendsparallel with those upper surfaces and straightly in the frontward andbackward direction. Each side portion 30 is interposed between anyadjacent two reinforcing beads 20 such that two side portions 30 arelocated on both sides of arbitrary one of the plurality of reinforcingbeads 20.

The vertically extending forward wall portion 26 of each bead-extendingportion 22 is a flat plate with a comparatively small and generallyrectangular shape having the same width as that of the upper bottom wallportion 24 and a length (i.e., a dimension as measured in the upward anddownward direction) that corresponds to substantially half a distancebetween the upper bottom wall portion 24 and the side portion 30. Thevertically extending forward wall portion 26 is formed integrally withthe corresponding upper bottom wall portion 24 so as to extend from itsfront-side edge in a vertically downward direction.

Each of the two side wall portions 28 of the bead-extending portion 22is an elongate flat plate. The two side wall portions 28 are formedintegrally with the corresponding upper bottom wall portion 24 so as toextend downward from respective widthwise opposite side edges of thesame 24 with a height that is substantially the same as the distancebetween the upper bottom wall portion 24 and the side portion 30.Further, the two side wall portions 28 are connected, at upper portionsof their front-side edges, integrally to respective widthwise oppositeside edges of the vertically extending forward wall portion 26.

In the meantime, the bead-end portion 23 of each reinforcing bead 20 isin the form of an inclined plate which extends from a rear-side edge ofthe upper bottom wall portion 24 of the corresponding bead-extendingportion 22 to a height position of the flat portion 14 while beinginclined at a predetermined angle. Each bead-end portion 23 isconnected, at its rear-side edge, integrally to a leading end of theflat portion 14 on a boundary line A (indicated by a two-dot line inFIG. 1) between the reinforcing portion 18 and the flat portion 14 ofthe base plate 12. Further, each bead-end portion 23 is connected, atits widthwise opposite side-edges, integrally to rear-side edges of therespective side wall portions 28 of the bead-extending portion 22.

Thus, each reinforcing bead 20 has a generally rectangular box-likeconfiguration extending upwardly and straightly in the frontward andbackward direction with the constant height. In other words, eachreinforcing bead 20 has a channel-like configuration that extendsstraightly in the forward and backward direction with an inverted U-likecross sectional shape which is taken along a plane perpendicular to thefrontward and backward direction and which is open downward. Theplurality of reinforcing beads 20 are arranged in the intermediateregion of the reinforcing portion 18 such that mutually opposing sidewall portions 28 of any adjacent two reinforcing beads 20 are spacedapart from each other in the leftward and rightward direction by apredetermined distance with the corresponding side portion 30 interposedtherebetween.

In the thus constructed leg-sweep apparatus 10, the plurality ofreinforcing beads 20 are formed integrally on the reinforcing portion 18of the base plate 12, thereby imparting a sufficiently high degree ofrigidity to the reinforcing portion 18, i.e., the front portion of thebase plate 12. Accordingly, the reinforcing portion 18 has increasedstrength with respect to flexing deformation.

As apparent from FIG. 1, in the present leg-sweep apparatus 10, thereare provided vertically extending forward wall portions 32 formed on thereinforcing portion 18 such that each of the vertically extendingforward wall portions 32 is formed integrally with the front-side edgeof a corresponding one of the side portions 30 which are located betweenany adjacent two reinforcing beads 20 so as to extend in the verticallyupward direction. The vertically extending forward wall portions 32 arearranged, in the leftward and rightward direction, side by side with thevertically extending forward wall portions 26 provided on the front-sideedges of the bead-extending portions 22 of the respective reinforcingbeads 20. According to the arrangement, the front surfaces of thevertically extending forward wall portions 26 of the respectivereinforcing beads 20 and the front surfaces of the vertically extendingforward wall portions 32 of the respective side portions 30 cooperatewith one another to provide a single continuous surface configuration inplan view. The thus formed continuous surface is made as a curved convexsurface that protrudes frontward corresponding to the inner surface of abumper cover of a front bumper described below. The front surfaces ofthe vertically extending wall portions 26, 32 which provide such acontinuous curved surface in plan view defines, under installation ofthe leg-sweep apparatus 10 on the vehicle, an impact-input surface 34 towhich is inputted an impact generated upon a collision of a pedestrianagainst the front face of the vehicle.

As shown in FIGS. 1 and 3, in the present leg-sweep apparatus 10, a rearportion of each reinforcing bead 20 is configured to have a gentlycurved S-like cross sectional shape taken along a plane perpendicular tothe leftward and rightward direction, the rear portion of thereinforcing bead 20 being constituted by the rear-side end section ofthe bead-extending portion 22 that extends horizontally in the frontwardand backward direction and the bead-end portion 23 that assumes aninclined plate form inclining downward in the backward direction.

Namely, a boundary portion between the upper bottom wall portion 24 ofthe bead-extending portion 22 and the bead-end portion 23 of eachreinforcing bead 20 is formed as a curved boundary portion 36 which isgently curved without being folded and which protrudes backward.Further, a connecting portion of the bead-end portion 23 of eachreinforcing bead 20 and the leading end of the flat portion 14 is formedas a curved connecting portion 40 which is gently curved without beingfolded and which protrudes frontward, the connecting portion beinglocated at a boundary portion 38 that extends over the rear-side endsection of the reinforcing portion 18 and the front-side end section ofthe flat portion 14 while including the boundary line A between thereinforcing portion 18 and the flat portion 14 of the base plate 12.

In the arrangement described above, an upper part of the inner surface(front surface) of each bead-end portion 23 is formed as a gently curvedconcave surface portion 41 protruding backward while a lower part of theinner surface (front surface) of each bead-end portion 23 is formed as acurved convex surface portion 43 protruding frontward. Further, anintermediate part of the inner surface (front surface) of each bead-endportion 23 between the upper part and the lower part is formed as aninclined surface portion 45 inclined downward in the backward directionfor connecting the concave curved surface portion 41 and the convexcurved surface portion 43.

Under installation of the thus constructed leg-sweep apparatus 10 on thevehicle described below, when a prescribed impact load is inputted tothe base plate 12, stress is advantageously distributed over theentirety of the curved boundary portion 36 constituted by the boundaryportion between the upper bottom wall portion 24 of the bead-extendingportion 22 and the bead-end portion 23 of each reinforcing bead 20 andthe entirety of the curved connecting portion 40 constituted by theconnecting portion between the bead-end portion 23 of each reinforcingbead 20 and the leading end of the flat portion 14.

Accordingly, the present leg-sweep apparatus 10 effectively eliminatesoccurrence of stress concentration at those boundary portion andconnecting portion, unlike the conventional apparatus in which theboundary portion between the upper bottom wall portion 24 of thebead-extending portion 22 and the bead-end portion 23 of eachreinforcing bead 20 and the connecting portion between the bead-endportion 23 of each reinforcing bead 20 and the leading end of the flatportion 14 are formed as angular folded portions.

When the vehicle on which is installed the thus constructed leg-sweepapparatus 10 runs, the air flow entering the inside of each reinforcingbead 20 from underneath the corresponding vertically extending forwardwall portion 26 and flowing through the reinforcing bead 20 in adirection indicated by an arrow B in FIG. 3 is brought into contact withthe inclined surface portion 45 and the convex curved surface portion43, in particular, and flows smoothly backward as indicated by an arrowC in FIG. 3 while being guided by the inclined surface portion 45 andthe convex curved surface portion 43. In the present leg-sweep apparatus10, therefore, it is possible to advantageously eliminate or mitigate anincrease in the air resistance arising from hard contact of the air flowentering the inside of each reinforcing bead 20 with the inner surfaceof the bead-end portion 23.

The leg-sweep apparatus 10 constructed as described above advantageouslyeliminates or mitigates local stress concentration at the base plate 12upon inputting of the impact load thereto and the increase in the airresistance during running of the vehicle on which the present leg-sweepapparatus 10 is installed. For those features indicated above, a radiusof curvature R₁ of the curved connecting portion 40 constituted by theconnecting portion between the bead-end portion 23 and the leading endof the flat portion 14 is significant. Therefore, it is desirable thatthe radius of curvature R₁ of the curved connecting portion 40 be notsmaller than 5 mm, thereby attaining distribution of the stress uponinputting of the impact load and reduction in the air resistance. Whilean upper limit value of the radius of curvature R₁ of the curvedconnecting portion 40 is not particularly limited, it is desirable thatthe radius of curvature R₁ of the curved connecting portion 40 be notlarger than 45 mm for the reasons described below. Namely, where theradius of curvature R₁ of the curved connecting portion 40 exceeds 45mm, the length of the bead-end portion 23 becomes excessively large,undesirably increasing the size (length) of each reinforcing bead 20including the bead-end portion 23 and accordingly the size (length) ofthe base plate 12 as a whole. In this instance, the leg-sweep apparatus10 tends to be large-sized. It is noted that a preferable range of theradius of curvature R₁ of the curved connecting portion 40 is from 10 mmto 30 mm.

For reasons similar to those explained above, a radius of curvature R₂of the curved boundary portion 36 constituted by the boundary portionbetween the upper bottom wall portion 24 of the bead-extending portion22 and the bead-end portion 23 in each reinforcing bead 20 is preferablyheld in a range from about 5 mm to about 45 mm, more preferably in arange from about 10 mm to about 30 mm, for instance.

The thus constructed leg-sweep apparatus 10 is disposed inside of afront bumper 42 installed on the front face of the vehicle according toa known structure, as shown in FIG. 4, for example.

The front bumper 42 inside of which is disposed the leg-sweep apparatus10 has a bumper cover 48 including an upper protruding portion 44 and alower protruding portion 46 which protrude from the front face of thevehicle in a state in which the front bumper 42 is installed on thefront face of the vehicle. Each of the upper and lower protrudingportions 44, 46 has, in vertical cross section, a convex curvedconfiguration protruding forward. The bumper cover 48 is fixed by boltsor the like to a front grille 50, for instance, that constitutes thefront face portion of the vehicle. In FIG. 4, the reference numerals 52,54 denote a bonnet and a radiator, respectively.

A known impact or shock-absorbing member 56 whose rigidity is smallerthan that of the leg-sweep apparatus 10 is disposed inside of the upperprotruding portion 44 of the bumper cover 48 such that theimpact-absorbing member 56 is fixedly interposed between the upperprotruding portion 44 and a bumper reinforcement 58 as a rigid member.

More specifically described, the leg-sweep apparatus 10 is disposed suchthat the front-side end section of the reinforcing portion 18 of theplate member 12 on which the plurality of reinforcing beads 20 areformed is inserted into the lower protruding portion 46 of the bumpercover 48 with the front-side end section projected forward from thefront face of the vehicle and such that, with the flat portion 14 of thebase plate 12 extended horizontally in the frontward and backwarddirection, the upper surface of the rear-side end section of the flatportion 14 is held in contact with the lower surface of a radiatorsupport 60 that is fixedly provided at a front portion of the vehicle soas to extend in the vehicle width direction for supporting a radiator54. Fixing bolts 62 are respectively inserted into the plurality ofinsertion holes 16 formed at the rear-side end section of the flatportion 14 and screwed into the radiator support 60, whereby the flatportion 14 of the base plate 12 is fixed at its rear-side end section tothe radiator support 60.

Thus, the leg-sweep apparatus 10 is disposed in the lower part of thefront face of the vehicle and fixedly positioned such that the entiretyof the base plate 12 is located to extend parallel with a horizontalplane which includes the input direction of the impact load to beinputted to the bumper cover 48 and such that the impact-input surface34 is opposed to the inner surface of the lower protruding portion 46 ofthe bumper cover 48 so as to be orthogonal to the input direction of theimpact load, the impact-input surface 34 being constituted by thevertically extending forward wall portions 26 provided at the front endsof the respective reinforcing beads 20 and the vertically extendingforward wall portions 32 provided at the front ends of the side portions30 each located between any adjacent two reinforcing beads 20.

In the leg-sweep apparatus 10 according to the present embodiment, whena leg portion 64 of the pedestrian comes into contact or collides withthe bumper cover 48 of the front bumper 42 as shown in FIG. 5, the upperprotruding portion 44 and the lower protruding portion 46 of the bumpercover 48 are respectively brought into contact with the vicinity of aknee 66 and the vicinity of a shank 68 of the leg portion 64 of thepedestrian. In this instance, since the rigidity of the impact-absorbingmember 56 is made smaller than that of the leg-sweep apparatus 10, theimpact-absorbing member 56 is deformed more easily in a larger amountthan the leg-sweep apparatus 10. Accordingly, the bumper cover 48 isdeformed such that the lower protruding portion 46 projects frontward ofthe vehicle farther than the upper protruding portion 44, so that thecounterforce with respect to the impact load generated in the leg-sweepapparatus 10 by the collision of the leg portion 64 against the bumpercover 48 acts on the vicinity of the shank 68 of the leg portion 64 ofthe pedestrian via the lower protruding portion 46 of the bumper cover48. As a result, the vicinity of the shank 68 of the leg portion 64 ofthe pedestrian is swept or scooped up by the leg-sweep apparatus 10,thereby causing the pedestrian to fall down or to be thrown toward thebonnet 52 of the vehicle. Thus, it is possible to limit bending of theknee 66 of the pedestrian in an unnatural or undesirable direction,thereby minimizing occurrence of injuries to the knee 66 such as bonefractures and effectively assuring protection and safety of thepedestrian.

In the present leg-sweep apparatus 10, in particular, the curvedconnecting portion 40 constituted by the connecting portion of thebead-end portion 23 of each reinforcing bead 20 and the flat portion 14is gently curved as described above, whereby it is possible to reduce oreliminate occurrence of stress concentration on the curved connectingportion 40 when the impact is inputted. Accordingly, the boundaryportion 38 between the reinforcing portion 18 and the flat portion 14 ofthe base plate 12 at which each curved connecting portion 40 is locatedis effectively prevented from being easily flexed or deformed by theinputted impact load generated upon collision of the leg portion 64 ofthe pedestrian against the bumper cover 48.

Further, in the present leg-sweep apparatus 10, the curved boundaryportion 36 constituted by the boundary portion between thebead-extending portion 22 and the bead-end portion 23 of eachreinforcing bead 20 is gently curved, whereby it is possible to reduceor eliminate occurrence of stress concentration on the curved boundaryportion 36 when the impact is inputted, thus enhancing the deformationstrength of the reinforcing portion 18.

Further, under installation of the leg-sweep apparatus 10 on thevehicle, the impact load is inputted orthogonally to the impact-inputsurface 34 of the reinforcing portion 18 that is disposed so as to beopposed to the inner surface of the lower protruding portion 46 of thebumper cover 48. Therefore, the arrangement is effective to preventgeneration of a force that acts, upon inputting of the impact load, onthe reinforcing portion 18 to lift the reinforcing portion 18 upward orlower the same 18 downward, thereby advantageously preventing easydeformation of the reinforcing portion 18 of the base plate 12 and theboundary portion 38 between the reinforcing portion 18 and the flatportion 14.

In the thus constructed leg-sweep apparatus 10, therefore, when theimpact load is inputted to the impact-input surface 34, the impact loadis applied to the flat portion 14 via the reinforcing portion 18 in asubstantially horizontal direction without suffering from flexingdeformation of the reinforcing portion 18 and the boundary portion 38,so that the flat portion 14 can undergo buckling deformation with highreliability and with high efficiency, obviating a delay in the rise ofthe impact load in the load characteristics.

Accordingly, the present leg-sweep apparatus 10 constructed as describedabove allows the impact load in the load characteristics to risepromptly and to reach the target value quickly, thereby effectivelyensuring excellent impact performance that permits a sufficiently highdegree of counterforce to be instantaneously exhibited with respect tothe impact load. As a result, the present leg-sweep apparatus 10 iscapable of promptly and reliably sweeping the leg portion of thepedestrian collided with the front face of the vehicle for protectingthe leg portion of the pedestrian with higher reliability.

In the leg-sweep apparatus 10 constructed as described above, the airflow which has entered the inside of each reinforcing bead 20 duringrunning of the vehicle on which the apparatus 10 is installed smoothlyflows backward while being guided by the inclined surface portion 45 andthe convex curved surface portion 43 of the inner surface of thebead-end portion 23 of each reinforcing bead 20, whereby the airresistance can be advantageously reduced, as compared with theconventional apparatus. Therefore, the present apparatus 10 achievesimproved aerodynamic characteristics and thereby realizes improvedrunning stability and improved fuel consumption of the vehicle.

The leg-sweep apparatus 10 according to the illustrated first embodimentmay be otherwise embodied.

In the illustrated first embodiment, all of the reinforcing beads 20 areconstituted to have the channel-like configuration which is opendownward. The direction in which the reinforcing beads 20 are open isnot particularly limited. Namely, all of the reinforcing beads 20 may beconstituted to have a channel-like configuration which is open upward.Alternatively, some of the reinforcing beads 20 may have thechannel-like configuration which is open downward while the rest of thereinforcing beads 20 may be constituted to have the channel-likeconfiguration which is open upward.

The cross sectional shape of each reinforcing bead 20 taken along theplane perpendicular to the frontward and backward direction is notlimited to the U-shape illustrated above, but may be arcuate, curved, orpolygonal, for instance. It is not necessary that the above-indicatedcross sectional shapes of the respective reinforcing beads 20 be madeidentical to each other.

In the illustrated first embodiment, the bead-end portion 23 of eachreinforcing bead 20 is in the form of an inclined plate which extendsbackward from the rear-side edge of the upper bottom wall portion 24 ofthe corresponding bead-extending portion 22 while being inclined. Thebead-end portion 23 may be configured to extend integrally from therear-side edge of the upper bottom wall portion 24 in the verticallydownward or vertically upward direction.

It is needles to mention that the number and the location of thereinforcing beads 20, the dimensions of constituent components of eachreinforcing bead 20 and the like may be suitably changed.

Where the number of the reinforcing beads 20 which are arranged parallelto each other in the leftward and rightward direction is increased bydecreasing the width of each reinforcing bead 20, the rigidity of thebase plate 12 is accordingly increased. Therefore, the rigidity of thebase plate 12 can be easily tuned by suitably adjusting the number ofthe reinforcing beads 20.

In the illustrated first embodiment, the entirety of the leg-sweepapparatus 10 is formed using the synthetic resin material. The materialof the leg-sweep apparatus 10 as the pedestrian protection apparatus isnot limited to the synthetic resin material. There may be used, forinstance, a metal material such as aluminum or an aluminum alloy whichis comparatively lightweight and excellent in formability.

The installation structure of the pedestrian protection apparatus (theleg-sweep apparatus 10) on the lower part of the front of the vehicle isnot particularly limited. Namely, the portion of the vehicle to whichthe rear portion (the flat portion 14) of the plate member (the baseplate 12) is fixed and the manner of fixing may be variously changed.

In the illustrated first embodiment, the counterforce with respect tothe impact load generated in the leg-sweep apparatus 10 by the collisionof the leg portion 64 of the pedestrian against the bumper cover 48 isarranged to act on the vicinity of the shank 68 of the leg portion 64 ofthe pedestrian via the lower protruding portion 46 of the bumper cover48. The portion of the leg portion 64 of the pedestrian on which thecounterforce with respect to the impact load acts may be suitablychanged depending upon the installation position of the leg-sweepapparatus 10.

It is noted that, in addition to the pedestrian protection apparatusdisposed inside of the bumper that is fixedly provided on the front faceof the automotive vehicles, the principle of the invention is applicableto any pedestrian protection apparatus such as those disposed at thefront face of the automotive vehicles independently of the bumper andthose installed in various forms on the front face of vehicles otherthan the automotive vehicles.

Example 1

For further clarification, there will be explained an example relatingto the illustrated first embodiment. It is to be understood that theinvention is not limited to the details of the example. Initially, therewas prepared, by carrying out injection molding using polypropylene, aleg-sweep apparatus shown in FIGS. 1-3. In the leg-sweep apparatus, eachreinforcing bead has a height of 10-15 mm and a width of 10-15 mm.Further, the radius of curvature R₁ of the curved connecting portionconstituted by the connecting portion between the bead-end portion ofeach reinforcing bead and the flat portion of the base plate is 12 mmwhile the radius of curvature R₂ of the curved boundary portionconstituted by the boundary portion between the bead-extending portionand the bead-end portion of each reinforcing bead is 20 mm. The thusprepared leg-sweep apparatus 10 was used as an invention apparatus.

For comparison, apart from the invention apparatus indicated above,there was prepared, by carrying out injection molding usingpolypropylene, a leg-sweep apparatus having a structure similar to thatdisclosed in the patent publication document JP-A-2002-264541 in whichboth of (1) the connecting portion of the bead-end portion of eachreinforcing bead and the flat portion of the base plate and (2) theboundary portion between the bead-extending portion and the bead-endportion of each reinforcing bead are formed as respective angular foldedportions. The thus prepared leg-sweep apparatus was used as aconventional apparatus. The height and the width of each reinforcingbead provided in the conventional apparatus are made equal to those inthe invention apparatus.

For each of the invention apparatus and the conventional apparatus,there was obtained, by Computational Fluid Dynamics (CFD), arelationship between resistance value generated in each apparatus andvelocity of air flow when each leg-sweep apparatus was positioned in theair flow flowing from the front toward the back. The results areindicated in FIG. 6.

As apparent from FIG. 6, the resistance value is kept smaller in theinvention apparatus than that in the conventional apparatus under thesame flow velocity. It is therefore clearly recognized that the airresistance can be advantageously reduced by forming the connectingportion between the bead-end portion of each reinforcing bead and theflat portion and the boundary portion between the bead-extending portionand the bead-end portion of each reinforcing bead, into the respectivegently curved configurations with no folded portions.

Further, the invention apparatus and the conventional apparatus wereactually installed on respective vehicles such that each apparatus wasdisposed inside of the bumper cover of the front bumper fixedly providedon the front face of each vehicle, as shown in FIG. 4. Thus, there wereprepared two test vehicles on which were installed the two leg-sweepapparatus having mutually different structures. Using the thus preparedtwo test vehicles, there were conducted pedestrian collision tests onthe supposition of a collision of a pedestrian with the front bumper ofeach test vehicle for examining, according to a known manner, changes inthe impact load with time inputted to each leg-sweep apparatus uponcollision of the pedestrian. The results are indicated in FIG. 7. Thepedestrian collision tests were conducted such that a dummy having aweight of 13.4 kg was collided with the front face of the front bumperof each test vehicle at a speed of 40 km/h.

As apparent from FIG. 7, it is recognized that the impact load promptlyreached the target value after collision of the pedestrian in the caseusing the invention apparatus, as compared with the case using theconventional apparatus. This clearly indicates that the counterforcewith respect to the impact load can be instantaneously and sufficientlyobtained in the leg-sweep apparatus according to the present invention.

2. Second Embodiment

Referring next to FIGS. 8 and 9, there will be explained a leg-sweepapparatus as the pedestrian protection apparatus constructed accordingto a second embodiment of the present invention. The leg-sweep apparatusgenerally indicated at 110 in FIGS. 8 and 9 is arranged to be installedinside of the front bumper which is disposed at the front face of theautomotive vehicle, like the leg-sweep apparatus 10 in the illustratedfirst embodiment. As apparent from FIGS. 8 and 9, the present leg-sweepapparatus 110 includes a base plate 112 as a plate member.

The base plate 112 is formed of a synthetic resin material such aspolypropylene or ABS resin and is constituted by a thin planar platehaving a generally rectangular shape. In the base plate 112, thedimension as measured in a direction extending in a leftward andrightward direction in FIG. 8, i.e., the dimension as measured in thevehicle width direction or the leftward and rightward (lateral)direction of the vehicle under installation of the leg-sweep apparatus110 on the vehicle, is made smaller than the vehicle width by a suitableamount, and the dimension as measured in a direction extending in anupward and downward direction in FIG. 8, i.e., the dimension as measuredin the frontward and backward direction of the vehicle (the vehiclelength or running direction), is made sufficiently smaller than theabove-indicated dimension as measured in the leftward and rightwarddirection. Hereinafter, the above-indicated direction extending in theleftward and rightward direction of the vehicle is referred to as “theleftward and rightward direction” while the above-indicated directionextending in the frontward and backward direction of the vehicle isreferred to as “the frontward and backward direction”.

In the base plate 112, a rear portion which occupies a substantiallyrear half region thereof is made as a flat portion 114 which has a flatplate-like configuration and which includes an upper surface and a lowersurface that extend horizontally under installation of the leg-sweepapparatus 110 on a vehicle. At a rear-side end of the flat portion 114,a plurality of insertion holes 116 (here, five insertion holes 116) intoeach of which a suitable fixing bolt is insertable are formed throughthe thickness of the flat portion 114 such that the insertion holes 116are spaced apart from each other by a suitable distance in the leftwardand rightward direction.

A front portion of the base plate 112 except for the flat portion 114 ismade as a reinforcing portion 118 having a reinforcement structure.Namely, there are formed a plurality of reinforcing beads 120 (here,seven reinforcing beads 120) integrally on an intermediate region of thereinforcing portion 118 except both side-end regions thereof in theleftward and rightward direction. The reinforcing beads 120 are adjacentto and spaced apart from each other by a constant distance in theleftward and rightward direction and provide a sufficient reinforcementstructure.

In detail, each reinforcing bead 120 is constituted by including abead-extending portion 122 which extends continuously in the frontwardand backward direction and a bead-end portion 123 which extends from arear-side edge of the bead-extending portion 123, as shown in FIGS.8-10.

The bead-extending portion 122 of each reinforcing bead 120 includes: anupper bottom wall portion 124; a vertically extending forward wallportion 126; and two side wall portions 128, 128. The upper bottom wallportion 124 generally has a rectangular shape having a comparativelysmall width and is located at a height position which is higher by asuitable distance than an upper surface of each of in-between sectionsof the reinforcing portion 118 that are located between any adjacent tworeinforcing beads 120 and the upper surface of the flat portion 114 thatis flush and continuous with the upper surface of each in-betweensection of the reinforcing portion 118, such that the upper bottom wallportion 124 extends parallel with those upper surfaces and straightly inthe frontward and backward direction. The vertically extending forwardwall portion 126 of each bead-extending portion 122 is formed integrallywith the corresponding upper bottom wall portion 124 so as to extendfrom its front-side edge in a vertically downward direction. The twoside wall portions 128 of each bead-extending portion 122 have arectangular shape and are formed integrally with the upper bottom wallportion 124 so as to extend in the vertically downward direction fromrespective widthwise opposite side edges of the same 124 with a suitableheight. Further, the two side wall portions 128 of each bead-extendingportion 122 are connected, at front-side edges thereof, integrally torespective widthwise opposite side edges of the vertically extendingforward wall portion 126.

In the meantime, the bead-end portion 123 of each reinforcing bead 120is in the form of an inclined plate which extends from a rear-side edgeof the upper bottom wall portion 124 of the corresponding bead-extendingportion 122 to a height position of the flat portion 114 while beinginclined, at a predetermined angle, downward in the backward direction.The bead-end portion 123 is connected, at its widthwise oppositeside-edges, integrally to the rear-side edges of the respective sidewall portions of the bead-extending portion 122. Further, bead-endportion 123 is connected, at its rear-side edge, integrally to theleading end of the flat portion 114.

Thus, each reinforcing bead 120 has a generally rectangular box-likeconfiguration extending upwardly and straightly in the frontward andbackward direction with the constant height. In other words, eachreinforcing bead 120 has a channel-like configuration that extendsstraightly in the frontward and backward direction with an invertedU-like cross sectional shape which is taken along a plane perpendicularto the frontward and backward direction and which is open downward.

The plurality of reinforcing beads 120 are arranged in the intermediateregion of the reinforcing portion 118 such that the side wall portions128 of the respective reinforcing beads 120 are opposed to and spacedapart from each other in the leftward and rightward direction by apredetermined distance. Each reinforcing bead 120 is connected, at arear-side edge of its bead-end portion 123, to the leading end of theflat portion 114 on a boundary line A (indicated by a two-dot line inFIG. 8) between the reinforcing portion 118 and the flat portion 114 ofthe base plate 120. This connecting portion between the bead-end portion123 of each reinforcing bead 120 and the flat portion 114 is made as abent portion 130 which extends in the leftward and rightward directionwith the same width as the reinforcing bead 120 and which protrudesdownward. In the leg-sweep apparatus 110, the bent portions 130 arelocated on the above-indicated boundary line A between the reinforcingportion 118 and the flat portion 114 of the base plate 112 so as to bespaced apart from each other by a predetermined distance in the leftwardand rightward direction.

In the thus constructed leg-sweep apparatus 110, the plurality ofreinforcing beads 120 are formed integrally on the reinforcing portion118 of the base plate 112, thereby imparting a sufficiently high degreeof rigidity to the reinforcing portion 118, i.e., the front portion ofthe base plate 112. Accordingly, the reinforcing portion 118 hasincreased strength with respect to flexing deformation.

As apparent from FIG. 8, in the present leg-sweep apparatus 110, thereare provided vertically extending forward wall portions 132 on thefront-side edge of the reinforcing portion 118 between any adjacent tworeinforcing beads 120, such that the vertically extending forward wallportions 132 extend in the vertically upward direction. The verticallyextending forward wall portions 132 are connected integrally to thevertically extending forward wall portions 126 provided on thefront-side edges of the bead-extending portions 122 of the respectivereinforcing beads 120. According to the arrangement, the front surfacesof the vertically extending forward wall portions 126 of the respectivereinforcing beads 120 and the front surfaces of the vertically extendingforward wall portions 132 provided on the front-side edge of thereinforcing portion 118 between any adjacent two reinforcing beads 120cooperate with one another to provide a single continuous surfaceconfiguration in plan view. The thus formed continuous surface is madeas a curved convex surface that protrudes frontward corresponding to theinner surface of the bumper cover of the front bumper. The frontsurfaces of the vertically extending wall portions 126, 132 whichprovide such a continuous curved surface in plan view defines, underinstallation of the leg-sweep apparatus 110 on the vehicle, animpact-input surface 134 to which is inputted an impact generated upon acollision of a pedestrian against the front face of the vehicle.

In the present leg-sweep apparatus 110, there are formed first throughfourth auxiliary beads 138, 140, 142, 144 at respective prescribedlocations of the base plate 112, for enhancing the strength of aboundary portion 136 which extends over the rear-side end section of thereinforcing portion 118 and the front-side end section of the flatportion 114 while including the boundary line A between the reinforcingportion 118 and the flat portion 114 of the base plate 112 and forenhancing the strength of a region of the reinforcing portion 118 of thebase plate 112 ranging from its intermediate section to its front-sideend section in the frontward and backward direction, for instance.

More specifically explained, as shown in FIGS. 8 and 11, a plurality offirst auxiliary beads 138 (here, seven first auxiliary beads 138) areformed integrally on the boundary portion 136 of the base plate 112 suchthat each of the first auxiliary beads 138 extends continuously in thefrontward and backward direction over the bead-end portion 123 of thecorresponding reinforcing bead 120 and the front-side end section of theflat portion 114. Further, a plurality of second auxiliary beads 140(here, seven second auxiliary beads 140) are formed integrally with therespective bead-extending portions 122 of the reinforcing beads 120.

Each of the first auxiliary beads 138 has a lower bottom wall portion146 and four side wall portions 148 located on the front side, the rearside, the left side, and the right side, respectively. The lower bottomwall portion 146 is a generally rectangular flat plate-likeconfiguration having a width sufficiently smaller than the width of theupper bottom wall portion 124 of the bead-extending portion 122 and thanthe width of the bead-end portion 123 and a length smaller than thelength of the reinforcing bead 120. The lower bottom wall portion 146 ofeach of the first auxiliary beads 138 is located below the lower surfaceof the flat portion 114 of the base plate 112 so as to extend in thefrontward and backward direction. Further, a lengthwise middle portionof the lower bottom wall portion 146 (a middle portion of the lowerbottom wall portion 146 in the frontward and backward direction) is bentat substantially the same angle as the bent portion 130 formed betweeneach bead-end portion 123 and the front-side end section of the flatportion 114 in the boundary portion 136 of the base plate 112. In thelower bottom wall portion 146 configured as described above, the lowersurface thereof located forward of the thus bent portion is formed as aninclined surface inclining downward in the backward direction, as shownin FIG. 11.

Each of the four side wall portions 148 of the first auxiliary bead 138is a flat plate having a rectangular or hexagonal shape and a heightsmaller than that of the side wall portions 128 of the bead-extendingportion 122 of each reinforcing bead 120. The four side wall portions148 extend in the vertically upward direction respectively from thefront-side edge portion, the rear-side edge portion, the left-side edgeportion, and the right-side edge portion of the lower bottom wallportion 146, so as to be connected integrally to the bead-end portion123 and the front-side end section of the flat portion 114.

Thus, each of the first auxiliary beads 138 has a generally rectangularbox-like configuration protruding downward in which the lengthwisemiddle portion is bent such that the forward portion is inclined upward.In other words, each first auxiliary bead 138 has a channel-likeconfiguration whose depth is smaller than that of each reinforcing bead120 and which extends in a bent form in the frontward and backwarddirection with a U-like cross sectional shape which is taken along theplane perpendicular to the frontward and backward direction and which isopen upward, i.e., which is open in a direction opposite to thedirection in which each reinforcing bead 120 is open. The thusconfigured first auxiliary beads 138 are provided integrally on theboundary portion 136 of the base plate 112 so as to correspond to therespective bent portions 130 formed at the boundary portion 136, suchthat each first auxiliary bead 138 extends continuously in the frontwardand backward direction across the corresponding bent portion 130.

In the meantime, each of the second auxiliary beads 140 has a lowerbottom wall portion 150 and three side wall portions 152 located on therear side, the left side, and the right side, respectively. The lowerbottom wall portion 150 has a generally rectangular flat plate-likeconfiguration having substantially the same width as the lower bottomwall portion 146 of each first auxiliary bead 138 and a lengthsufficiently smaller than that of the upper bottom wall portion 124 ofthe bead-extending portion 122 of each reinforcing bead 120. Each lowerbottom wall portion 150 extends straightly in the frontward and backwarddirection at a height position which is lower, by a suitable distance,than the lower surface of the upper bottom wall portion 124 of thecorresponding bead-extending portion 122 and which is higher, by asuitable distance, than the upper surface of intermediate parts of thereinforcing portion 118 located between any adjacent two reinforcingbeads 120. Further, the lower bottom wall portion 150 is connected, atits front edge, integrally to the back surface of the correspondingvertically extending forward wall portion 126 of the bead-extendingportion 122. Each of the three side wall portions 152 of the secondauxiliary bead 140 is a flat plate with a rectangular shape and has aheight smaller than the height of the side wall portions 128 of thebead-extending portion 122 of each reinforcing bead 120. The three sidewall portions 152 extend in the vertically upward direction from therespective rear-side, left-side and right-side edges of the lower bottomwall portion 150 so as to be connected integrally to the correspondingupper bottom wall portion 124 of the bead-extending portion 122.

Thus, each of the second auxiliary beads 140 has a generally rectangularbox-like configuration which protrudes downward and which straightlyextends in the frontward and backward direction with the constant heightthat is smaller than the height of each reinforcing bead 120. In otherwords, each second auxiliary bead 140 has a channel-like configurationwhose depth is smaller than that of each reinforcing bead 120 and whichstraightly extends in the frontward and backward direction with a U-likecross sectional shape which is taken along the plane perpendicular tothe frontward and backward direction and which is open upward, i.e.,which is open in a direction opposite to the direction in which eachreinforcing bead 120 is open. The thus configured second auxiliary beads140 are provided so as to be spaced apart from each other in theleftward and rightward direction on a region of the reinforcing portion118 of the base plate 112 including its intermediate section and itsfront-side end section except its rear-side end section, such that eachsecond auxiliary bead 140 is formed integrally on the widthwise middlesection of the upper bottom wall portion 124 of the bead-extendingportion 122 of the corresponding reinforcing bead 120.

In the meantime, the third auxiliary beads 142 and the fourth auxiliarybeads 144 are formed on respective intermediate parts of the base plate112 each of which is located between the corresponding two adjacentreinforcing beads 120, such that the third and fourth auxiliary beads142, 144 extend in the frontward and backward direction, as shown inFIGS. 8 and 12.

Each of the third auxiliary beads 142 has an upper bottom wall portion154 and four side wall portions 156 located on the front side, the rearside, the left side, and the right side, respectively. Each upper bottomwall portion 154 has a generally rectangular flat plate-likeconfiguration having substantially the same width and length as thelower bottom wall portion 146 of each first auxiliary bead 138. Eachupper bottom wall portion 154 is located at a height position which ishigher, by a suitable distance, than the upper surface of intermediateparts of the reinforcing portion 118 located between any adjacent tworeinforcing beads 120 and than the upper surface of the flat portion 114that is flush and continuous with the upper surface of theabove-indicated intermediate sections of the reinforcing portion 118 andwhich is lower, by a suitable distance, than the lower surface of theupper bottom wall portion 124 of the bead-extending portion 122 of eachreinforcing bead 120. Each upper bottom wall portion 154 extendsparallel with those surfaces and straightly in the frontward andbackward direction. Each of the four side wall portions 156 is a flatplate having a rectangular shape and has a height smaller than that ofthe side wall portions 128 of the bead-extending portion 122 of eachreinforcing bead 120. The four side wall portions 156 extend in thevertically downward direction from the respective rear-side, left-sideand right-side edges of the upper bottom wall portion 154 so as to beconnected integrally to the rear-side end section of the reinforcingportion 118 and the front-side end section of the flat portion 114.

Thus, each of the third auxiliary beads 142 has a generally rectangularbox-like configuration which protrudes upward and which extendsstraightly in the frontward and backward direction with the constantheight that is smaller than the height of each reinforcing bead 120. Inother words, each third auxiliary bead 142 has a channel-likeconfiguration whose depth is smaller than that of each reinforcing bead120 and which extends straightly in the frontward and backward directionwith an inverted U-like cross sectional shape which is taken along theplane perpendicular to the frontward and backward direction and which isopen downward, i.e., which is open in the same direction as thedirection in which each reinforcing bead 120 is open. The thusconfigured third auxiliary beads 142 extend continuously in thefrontward and backward direction across the boundary line A, such thateach third auxiliary bead 142 is provided between the corresponding twoof the plurality of bent portions 130 formed on the boundary line A ofthe boundary portion 136 of the base plate 112, so as to be parallelwith and spaced apart from, by a prescribed distance in the leftward andrightward direction, the first auxiliary beads 138 which are located soas to correspond to the respective bent portions 130.

Each of the fourth auxiliary beads 144 has an upper bottom wall portion158 and three side wall portions 160 located on the rear side, the leftside, and the right side, respectively. The upper bottom wall portion158 has a generally rectangular flat plate-like configuration havingsubstantially the same width and length as those of the second auxiliarybeads 140. The upper bottom wall portion 158 of each fourth auxiliarybead 144 is located at a height position which is higher, by a suitabledistance, than the upper surface of the intermediate parts of thereinforcing portion 118 located between any adjacent two reinforcingbeads 120 and which is lower, by a suitable distance, than the lowersurface of the upper bottom wall portion 124 of the bead-extendingportion 122 of each reinforcing bead 120. Each upper bottom wall portion158 extends parallel with those surfaces and straightly in the frontwardand backward direction. Each of the three side wall portions 160 is aflat plate having a rectangular shape and has a height smaller than thatof the side wall portions 128 of the bead-extending portion 122 of eachreinforcing bead 120. The three side wall portions 160 of each fourthauxiliary bead 144 extend in the vertically downward direction from therespective rear-side, left-side, and right-side edges of the upperbottom wall portion 158 so as to be connected integrally to theintermediate part of the reinforcing portion 118 located between thecorresponding two adjacent reinforcing beads 120.

Thus, each of the fourth auxiliary beads 144 has a generally rectangularbox-like configuration which protrudes upward and which extendsstraightly in the frontward and backward direction with the constantheight that is smaller than the height of each reinforcing bead 120. Inother words, each fourth auxiliary bead 144 has a channel-likeconfiguration whose depth is smaller than that of each reinforcing bead120 and which extends straightly in the frontward and backward directionwith an inverted U-like cross sectional shape which is taken along theplane perpendicular to the frontward and backward direction and which isopen downward, i.e., which is open in the same direction as thedirection in which each reinforcing bead 120 is open. The thusconfigured fourth auxiliary beads 144 are provided on a region of thereinforcing portion 118 ranging from its intermediate section to itsfront-side end section in the frontward and backward direction, suchthat each fourth auxiliary bead 142 is disposed between thecorresponding two reinforcing beads 120 so as to be spaced apart in theleftward and rightward direction by a prescribed distance.

In the leg-sweep apparatus 110 constructed according to the exemplarysecond embodiment, the first auxiliary beads 138 are formed at theboundary portion 136 of the base plate 112 such that each firstauxiliary bead 138 extends in the frontward and backward directionacross the corresponding bent portion 130 formed between the bead-endportion 123 of the reinforcing bead 120 and the front-side end sectionof the flat portion 114. Thus, the bent portions 130 are reinforced bythe respective first auxiliary beads 138.

Further, each of the first auxiliary beads 138 has a generallyrectangular box-like configuration and is connected integrally to theboundary portion 136 of the base plate 112 at the upper ends of therespective four side wall portions 148 remote from the lower bottom wallportion 146. Therefore, when a suitable impact load is inputted to thebase plate 112 under installation of the leg-sweep apparatus 110 on thevehicle as described below, the stress generated in the vicinity of eachbent portion 130 is distributed over four locations corresponding to thefour corner portions formed by the four side wall portions 148 of eachfirst auxiliary bead 138. Accordingly, the stress generated at thosefour locations can be advantageously reduced or mitigated.

Further, the width of each first auxiliary bead 138 is smaller than thatof the bead-end portion 123 of each reinforcing bead 120. Accordingly,even if the connecting portion of the rear-end side wall portion 148 ofeach first auxiliary bead 138 and the flat portion 114 is bent, thewidth of such a bent section can be made small. Accordingly, the stressto be generated at such a bent section upon inputting of the impact doesnot become large to such an extent that causes a serious problem.

In the present leg-sweep apparatus 110, therefore, under installationthereof on the automotive vehicle as described below, it is possible toadvantageously reduce or eliminate the stress concentration at each bentportion 130 and its vicinity when a suitable impact load is inputted tothe base plate 112.

In the exemplary second embodiment, the third auxiliary beads 142 areprovided integrally on the boundary portion 136 of the base plate 112such that each third auxiliary bead 142 extends continuously in thefrontward and backward direction across the boundary line A between thereinforcing portion 118 and the flat portion 114 where the bent portions130 are located while being disposed adjacent to the first auxiliarybeads 138 in the leftward and rightward direction. Accordingly, thedeformation strength of the boundary portion 136 of the base plate 112,especially in the vicinity of the boundary line A, can be advantageouslyincreased.

Further, in the present leg-sweep apparatus 110, the second auxiliarybeads 140 are formed integrally with the bead-extending portions 122 ofthe respective reinforcing beads 120 provided on the reinforcing portion118, so as to extend in the frontward and backward direction, therebyreinforcing the bead-extending portions 122 of the reinforcing beads120. Moreover, each of the fourth auxiliary beads 144 is formed so as toextend in the frontward and backward direction between thebead-extending portions 122 of the corresponding adjacent tworeinforcing beads 120 reinforced by the respective second auxiliarybeads 140. Accordingly, each of portions of the base plate 112 which arelocated between two bead-extending portions 122 of any adjacent tworeinforcing beads 120 is sufficiently reinforced. Accordingly, thedeformation strength of parts of the reinforcing portion 118 of the baseplate 112 at which the bead-extending portions 122 of the reinforcingbeads 120 are formed can be more effectively increased.

The thus constructed leg-sweep apparatus 110 is disposed inside of thefront bumper 42 installed on the front face of the vehicle, as shown inFIG. 13, for example. Because the structure of the front bumper 42inside of which the leg-sweep apparatus 110 is disposed is the same asthat explained with respect the illustrated first embodiment, itsdetailed description is dispensed with. The front bumper 42 is installedon the front face of the vehicle as explained above with respect to theillustrated first embodiment.

As in the illustrated first embodiment, the impact or shock-absorbingmember 56 whose rigidity is smaller than that of the leg-sweep apparatus110 is disposed inside of the upper protruding portion 44 of the bumpercover 48 such that the impact-absorbing member 56 is fixedly interposedbetween the upper protruding portion 44 of the bumper cover 48 and thebumper reinforcement 58 as a rigid member.

More specifically described, the leg-sweep apparatus 110 is disposedsuch that the front-side end section of the reinforcing portion 118 ofthe base plate 112 on which are formed the reinforcing beads 20, thesecond auxiliary beads 140, and the fourth auxiliary beads 144 isinserted into the lower protruding portion 46 of the bumper cover 48with the front-side end section projected forward from the front face ofthe vehicle and such that, with the flat portion 114 of the base plate112 extended horizontally in the frontward and backward direction, theupper surface of the rear-side end section of the flat portion 114 isheld in contact with the lower surface of the radiator support 60 thatis fixedly provided at the front portion of the vehicle so as to extendin the vehicle width direction for supporting the radiator 54. Thefixing bolts 60 are respectively inserted into the plurality ofinsertion holes 116 formed at the rear-side end section of the flatportion 114 and screwed into the radiator support 60, whereby the flatportion 114 of the base plate 112 is fixed at its rear-side end sectionto the radiator support 60.

Thus, the leg-sweep apparatus 110 is disposed in the lower part of thefront face of the vehicle and fixedly positioned such that the entiretyof the base plate 112 is located to extend parallel with the horizontalplane which includes the input direction of the impact load to beinputted to the bumper cover 48 and such that the impact-input surface134 is opposed to the inner surface of the lower protruding portion 46of the bumper cover 48 so as to be orthogonal to the input direction ofthe impact load, the impact-input surface 134 being constituted by thevertically extending forward wall portions 126 provided at the frontends of the respective reinforcing beads 120 and the verticallyextending forward wall portions 132 provided at the front ends of theintermediate parts of the reinforcing portion 118 each located betweenany adjacent two reinforcing beads 120.

In the leg-sweep apparatus 110 according to the exemplary secondembodiment, when the leg portion 64 of the pedestrian comes into contactor collides with the bumper cover 48 of the front bumper 42 as shown inFIG. 14, the upper protruding portion 44 and the lower protrudingportion 46 of the bumper cover 48 are respectively brought into contactwith the vicinity of the knee 66 and the vicinity of the shank 68 of theleg portion 64 of the pedestrian. In this instance, since the rigidityof the impact-absorbing member 56 is made smaller than that of theleg-sweep apparatus 110, the impact-absorbing member 56 is deformed moreeasily in a larger amount than the leg-sweep apparatus 110. Accordingly,the bumper cover 48 is deformed such that lower protruding portion 46projects frontward of the vehicle farther than the upper protrudingportion 44, so that the counterforce with respect to the impact loadgenerated in the leg-sweep apparatus 110 by the collision of the legportion 64 against the bumper cover 48 acts on the vicinity of the shank68 of the leg portion 64 of the pedestrian via the lower protrudingportion 46 of the bumper cover 48. As a result, the vicinity of theshank 68 of the leg portion 64 of the pedestrian is swept or scooped upby the leg-sweep apparatus 110, thereby causing the pedestrian to falldown or to be thrown toward the bonnet 52 of the vehicle. Thus, it ispossible to limit bending of the knee 66 of the pedestrian in anunnatural or undesirable direction, thereby minimizing occurrence ofinjuries to the knee 66 such as bone fractures and effectively assuringprotection and safety of the pedestrian.

In the present leg-sweep apparatus 110, in particular, the plurality offirst and third auxiliary beads 138, 142 are provided at the boundaryportion 136 of the base plate 12, whereby it is possible to reduce oreliminate occurrence of the stress concentration on the bent portions130 at the boundary portion 136 upon inputting of the impact load whileadvantageously increasing the deformation strength of the boundaryportion 136. Therefore, the boundary portion 136 of the base plate 112is effectively prevented from being easily flexed or deformed by theinputted impact load generated upon collision of the leg portion 64 ofthe pedestrian against the bumper cover 48.

Further, the plurality of second auxiliary beads 140 and the pluralityof fourth auxiliary beads 144 are provided at the region of thereinforcing portion 118 ranging from its front-side end section to itsintermediate section, thereby increasing the deformation strength of theabove-indicated region. Accordingly, it is possible to effectivelyprevent the front-side end section of the reinforcing portion 118 frombeing easily deformed upon inputting of the impact load.

Further, under installation of the leg-sweep apparatus 110 on thevehicle, the impact load is inputted orthogonally to the impact-inputsurface 134 of the reinforcing portion 118 that is disposed so as to beopposed to the inner surface of the lower protruding portion 46 of thebumper cover 48. The arrangement is effective to prevent generation of aforce that acts, upon inputting of the impact load, on the reinforcingportion 118 to lift the reinforcing portion 118 upward or lower the same118 downward, thereby advantageously preventing easy deformation of thereinforcing portion 118 and the boundary portion 136 of the base plate112.

In the thus constructed leg-sweep apparatus 110, therefore, when theimpact load is inputted to the impact-input surface 134, the impact loadis applied to the flat portion 114 via the reinforcing portion 118 in asubstantially horizontal direction without suffering from flexingdeformation of the reinforcing portion 118 and the boundary portion 136,so that the flat portion 114 can undergo buckling deformation with highreliability and with high efficiency, obviating a delay in the rise ofthe impact load in the load characteristics.

Accordingly, the present leg-sweep apparatus 110 constructed asdescribed above allows the impact load in the load characteristics torise promptly and to reach the target value quickly, thereby effectivelyensuring excellent impact performance that permits a sufficiently highdegree of counterforce to be instantaneously exhibited with respect tothe impact load. As a result, the present leg-sweep apparatus 110 iscapable of promptly and reliably sweeping of the leg portion of thepedestrian collided with the front face of the vehicle for protectingthe leg portion of the pedestrian with higher reliability.

In the present leg-sweep apparatus 110, the height or the width of eachof the first through fourth auxiliary beads 138-144 is made sufficientlysmaller than the height of each reinforcing bead 120. In addition, eachof the second auxiliary beads 140 formed on the upper bottom wallportion 124 of the bead-extending portion 122 of the correspondingreinforcing bead 120 has the U-like cross sectional shape which is takenalong the plane perpendicular to the frontward and backward directionand which is open upwards, i.e., which is open in a direction oppositeto the direction of opening of each reinforcing bead 120 having theinverted U-like cross sectional shape taken along the above-indicatedplane and opening downward. Therefore, the height of the base plate 112including the reinforcing beads 120 and the auxiliary beads 138-144 isnot increased and accordingly the size of the leg-sweep apparatus 110 asa whole is not increased, by provision of the first through fourthauxiliary beads 138-144 on the base plate 112 and by provision of thesecond auxiliary beads 140 on the bead-extending portions 122 of thereinforcing beads 120 having the predetermined height. In consequence,the arrangement effectively achieves improved impact performance withoutsuffering from an increase in the size of the leg-sweep apparatus 110 asa whole and an increase in the size of the metal molds used for formingthe leg-sweep apparatus 110 arising from the size increase of theleg-sweep apparatus 110.

The leg-sweep apparatus 110 according to the illustrated secondembodiment may be otherwise embodied.

The direction of opening of each of the first through fourth auxiliarybeads 138-144 having the above-indicated U-like or inverted U-like crosssectional shape is not limited to those illustrated above. For instance,at least one of the first auxiliary beads 138 and the second auxiliarybeads 140 may be constituted to have an inverted U-like cross sectionalshape taken along the plane perpendicular to the frontward and backwarddirection and opening downward while at least one of the third auxiliarybeads 142 and the fourth auxiliary beads 144 may be constituted to havea U-like cross sectional shape taken along the above-indicated plane andopening upward.

The cross sectional shape of each of the first through fourth auxiliarybeads 138-144 taken along the plane perpendicular to the frontward andbackward direction is not limited to the U-shape illustrated above, butmay be arcuate, curved, or polygonal, for instance. It is not necessarythat the above-indicated cross sectional shape of each of the auxiliarybeads 138-144 be made identical to each other.

In the illustrated second embodiment, each of the first through fourthauxiliary beads 138-144 is constituted independently of each other.However, the auxiliary bead 138 and the second auxiliary bead 140 may becontinuous with each other or the third auxiliary bead 142 and thefourth auxiliary bead 144 may be continuous with each other, forinstance. In other words, there may be formed, on the base plate 112,auxiliary beads each of which continuously extends in the frontward andbackward direction over the front-end section of the flat portion 114 asthe rear portion of the base plate 112 and the bead-end andbead-extending portions 123, 122 of each reinforcing bead 120. Further,there may be formed auxiliary beads each of which is located between thecorresponding two reinforcing beads 120 so as to continuously extend inthe frontward and backward direction from the front-side end section ofthe reinforcing portion 118 as the front portion of the base plate 112to the front-side end section of the flat portion 114.

The second auxiliary bead 140 provided on the bead-end portion 122 ofeach reinforcing bead 120 and the fourth auxiliary bead 144 provided oneach intermediate part of the reinforcing portion 118 located betweenthe corresponding two adjacent reinforcing beads 120 may be divided intoa plurality of sections arranged in series in the frontward and backwarddirection.

The width of each of the auxiliary beads 138-144 is not particularlylimited, provided that the width is made smaller than that of eachreinforcing bead 120.

In the illustrated second embodiment, the first and second auxiliarybeads 138, 140 are provided such that one first auxiliary bead 138 andone second auxiliary bead 140 correspond to one reinforcing bead 120. Aplurality of first auxiliary beads 138 and a plurality of secondauxiliary beads 140 may be provided for one reinforcing bead 120, so asto be arranged side by side in the leftward and rightward direction. Thethird and fourth auxiliary beads 142, 144, each being provided betweenany adjacent two reinforcing beads 120, may be provided such that aplurality of third auxiliary beads 142 and a plurality of fourthauxiliary beads 144 may be disposed between any adjacent two reinforcingbeads 120 so as to be arranged in the frontward and backward directionor the leftward and rightward direction.

In the illustrated second embodiment, each of the reinforcing beads 120has the channel-like configuration that is open downward. Thereinforcing bead 120 may be constituted to have a channel-likeconfiguration that is open upward.

Moreover, the reinforcing beads 120 may be constituted as shown in FIGS.15 and 16. More specifically explained, first reinforcing beads 120 aeach having the channel-like configuration that is open downward andsecond reinforcing beads 120 b each having the channel-likeconfiguration that is open upward may be alternately provided in theleftward and rightward direction on the reinforcing portion 118 of thebase plate 112. When such a construction is employed, the firstauxiliary beads 138 a and the second auxiliary beads 140 a are formedintegrally on the base plate 112 such that the first auxiliary bead 138and the second auxiliary bead 140 are provided for each firstreinforcing bead 120 a and such that the first auxiliary bead 138 andthe second auxiliary bead 140 are provided for each second reinforcingbead 120 b. In the leg-sweep apparatus 110 shown in FIGS. 15 and 16, thefirst auxiliary bead 138 a and the second auxiliary bead 140 a providedfor each first reinforcing bead 120 a have a channel-like configurationthat is open upward while the first auxiliary bead 138 b and the secondauxiliary bead 140 b provided for each second reinforcing bead 120 bhave a channel-like configuration that is open downward. According tothe arrangement, the height of the leg-sweep apparatus 110 is minimized,avoiding an increase in the size of the apparatus 110 as a whole. InFIGS. 15 and 16, the same reference numerals as used in FIGS. 8 and 9are used to identify the corresponding components, and a detailedexplanation of which is dispensed with.

In the illustrated second embodiment, the bead-end portion 123 of eachreinforcing bead 120 is in the form of an inclined plate which extendsintegrally from the rear-side edge of the corresponding upper bottomwall portion 124 so as to incline downward in the backward direction.The bead-end portion 123 may be configured to extend integrally from therear-side edge of the upper bottom wall portion 124 in the verticallydownward direction.

It is needless to mention that the number, the location, and the shapeof the reinforcing beads 120, the dimensions of the constituentcomponents of each reinforcing bead 120, etc., may be suitably changed.

Where the number of the reinforcing beads 120 and the number of theauxiliary beads 138-144, especially the numbers thereof arranged inparallel in the leftward and rightward direction, are increased, therigidity of the base plate 112 can be accordingly increased. Therefore,the rigidity of the base plate 112 can be easily tuned by suitablyadjusting the numbers of the reinforcing beads 120 and the auxiliarybeads 138-144.

In the illustrated second embodiment, the entirety of the leg-sweepapparatus 110 is formed using the synthetic resin material. The materialof the leg-sweep apparatus 110 as the pedestrian protection apparatus isnot limited to the synthetic resin material. There may be used, forinstance, a metal material such as aluminum or an aluminum alloy whichis comparatively lightweight and excellent in formability.

The installation structure of the pedestrian protection apparatus (theleg-sweep apparatus 110) on the lower part of the front of the vehicleis not particularly limited. Namely, the portion of the vehicle to whichthe rear portion of the plate member (the base plate 112) is fixed andthe manner of fixing may be variously changed.

In the illustrated second embodiment, the counterforce with respect tothe impact load generated in the leg-sweep apparatus 110 by thecollision of the leg portion 64 of the pedestrian against the bumpercover 48 is arranged to act on the vicinity of the shank 68 of the legportion 64 of the pedestrian via the lower protruding portion 46 of thebumper cover 48. The portion of the leg portion 64 of the pedestrian onwhich the counterforce with respect to the impact load acts may besuitably changed depending upon the installation position of theleg-sweep apparatus 110.

It is noted that, in addition to the pedestrian protection apparatusdisposed inside of the bumper that is fixedly provided on the front faceof the automotive vehicles, the principle of the invention is applicableto any pedestrian protection apparatus such as those disposed at thefront face of the automotive vehicles independently of the bumper andthose installed in various forms on the front face of vehicles otherthan the automotive vehicles

Example 2

For further clarification, there will be explained an example relatingto the illustrated second embodiment. It is to be understood that theinvention is not limited to the details of the example. Initially, therewas prepared, by carrying out injection molding using polypropylene, aleg-sweep apparatus shown in FIGS. 8-12. In the leg-sweep apparatus,each reinforcing bead has a height of 30 mm and a width of 30 mm whileeach of the first through fourth auxiliary beads has a height of 5 mmand a width of 10 mm. Further, the base plate has a thickness of 2.7 mm.The thus prepared leg-sweep apparatus was used as an inventionapparatus.

For comparison, apart from the invention apparatus indicated above,there was prepared, by carrying out injection molding usingpolypropylene, a leg-sweep apparatus having a structure similar to thatdisclosed in the patent publication document JP-A-2002-284741 in whichonly reinforcing beads are formed integrally on the front portion (thereinforcing portion) of the base plate so as to be equally spaced apartfrom each other in the leftward and rightward direction, with no firstthrough fourth auxiliary beads provided. The thus prepared leg-sweepapparatus was used as a conventional apparatus. The height and the widthof each reinforcing bead and the thickness of the base plate in theconventional apparatus are made equal to those in the inventionapparatus.

The thus prepared invention apparatus and conventional apparatus wereactually installed on respective vehicles such that each apparatus wasdisposed inside of the bumper cover of the front bumper fixedly providedon the front face of each vehicle, as shown in FIG. 13. Thus, there wereprepared two test vehicles on which were installed the two leg-sweepapparatus having mutually different structures. Using the thus preparedtwo test vehicles, there were conducted pedestrian collision tests onthe supposition of a collision of a pedestrian with the front bumper ofeach test vehicle for examining, according to a known manner, changes inthe impact load with time inputted to each leg-sweep apparatus uponcollision of the pedestrian. The results are indicated in FIG. 17. Thepedestrian collision tests were conducted such that a dummy having aweight of 13.4 kg was collided with the front face of the front bumperof each vehicle at a speed of 40 km/h.

As apparent from FIG. 17, it is recognized that the impact load promptlyreached the target value after collision of the pedestrian in the caseusing the invention apparatus, as compared with the case using theconventional apparatus. This clearly indicates that the counterforcewith respect to the impact load can be instantaneously and sufficientlyobtained in the leg-sweep apparatus according to the present invention.

It is to be understood that the present invention may be embodied withvarious other changes and modifications which may occur to those skilledin the art, without departing from the spirit and scope of the inventiondefined in the following claims.

1. A pedestrian protection apparatus for a vehicle, comprising: a platemember which is disposed at a lower part of a front of the vehicle so asto extend in a frontward and backward direction of the vehicle, whichincludes a front portion and a rear portion, and which is fixed at therear portion to the vehicle; and at least one reinforcing bead eachformed integrally on the front portion of the plate member and eachincluding a bead-extending portion which extends in the frontward andbackward direction of the vehicle with a channel-like configuration thatis open upward or downward and a bead-end portion which has a plate-likeconfiguration and which extends integrally from a rear-side edge of thebead-extending portion for connecting the rear-side edge of thebead-extending portion and the rear portion of the plate member, theapparatus being arranged to sweep a leg portion of a pedestrian that hascollided with the front of the vehicle by contact of a front end of theplate member with the leg portion of the pedestrian, thereby protectingthe leg portion of the pedestrian, wherein a connecting portion betweenthe bead-end portion of each of the at least one reinforcing bead andthe rear portion of the plate member is gently curved without beingfolded.
 2. The apparatus according to claim 1, wherein the bead-endportion of each of the at least one reinforcing bead is an inclined flatplate or an inclined curved plate extending from the rear-side edge ofthe bead-extending portion toward the rear portion of the plate member.3. The apparatus according to claim 1, wherein a boundary portionbetween the bead-extending portion and the bead-end portion of each ofthe at least one reinforcing bead is gently curved without being folded.4. The apparatus according to claim 1, wherein each of the at least onereinforcing bead further includes, at a forward end thereof, a forwardwall portion which is formed integrally with the bead-extending portionof a corresponding one of the at least one reinforcing bead, which has afront surface extending in a vertical direction, and which constitutesat least a part of the front end of the plate member.